If you have a band you got to have 3 or 4 drummers and 3 or 4 bass players
That's one hell of band. I have drummed in many bands as the solo drummer, usually with one bass player, never two, and never another drummer except for maybe a little percussion added here or there by the guy with little to do, often the guy on keys or another guitarist. Nearly all the bands I listen to have one drummer and one bass player
I have to say you haven't spent much time in the trenches. Or in fact you are a drummer. One who hangs out with musicians.
You don't have 3 or 4 drummers and 3 or 4 bass players at the same gig. You have a rolodex of musicians who can fill in. You only have 1 drummer and one bass player at a show.
I have never been in a successful money making band that only had 1 drummer.
And I have been playing since the beatles came out.
There have been bands like the grateful dead and alman brothers that would show up with 2 drummers. I guess they figured having 2 one would always show up and be there.
If it is a successful band the person or management running it. Has back ups for everybody.
I guess what I am saying is of all the people that hang out with musicians. Drummers are the least reliable for various reasons. And you need to have a number of them in your rolodex if you want your band to be known as a dependable band that doesn't cancel gigs.